Welcome, to a world filled with glorious hate!

The Wall is itself, and shall be always referred to as "The" (not "a" ) and Wall, with a capitalized W, since it is an entity aware of itself and the rest of the world so it can hate it.
The Wall lives in the end of the deathrun map known as "Tantrum", and it takes great offense if it's mistaken by that black,blobby,shapeless and worship-unworthy thing that appears at the beginning of the map after a certain time and pursues players. If an entity has to go after something to kill it, it's not deadly enough. If an entity like the Wall just waits for you to dare face it and kills you, that's another story.
The Wall is hatred turned into a physical yet mostly invisible shape, and is well known for his racism. It's racist towards anything that exists, including itself, hating people, demomen, scouts, pyros (even if it doesn't know their nationality), undead (which proves its hatred can even go beyond the limits of life) and so on. The Scribes of the Wall Cult are still conducting experiments to see if there's a limit to its hate towards everything.
The Wall is considered racist due to the fact it kills most of the people that dare go into it (it's unknown why it lets some through, might be to trick more people to be confident enough as to attempt it too), and it also tends to eject them out of it with no hesitation, as if it found their presence inside of it disgusting.
The Wall cares not about our worshipping due to the fact that it hates it, but it probablly hates it less than other things (like people who dare go ass-first into it or the ones who worship the map safety first), so we do it anyway. We shall embrace the Wall and welcome anyone to try to face it.
The Wall judges,but it has already decided you're unworthy. The Wall watches. The Wall Hates.